The VERY common ingredient that really could stave off ageing – and even diseases like dementia, by PROFESSOR ROB GALLOWAY

I’ll admit it, I’m vain: I’m worried about getting old, not just because of the decline in health and energy levels but, yes, about how I look.

So I’m trying to do things that can slow down these inevitable changes.

Billions have been thrown into anti-ageing research, with lots of talk about this supplement or that.

I’ve spent the last few years reading about and analysing the data behind these latest developments, looking for my own, evidence-based elixir of youth.

You might call it a vanity project, but the reality is I’ve spent a career in A&E seeing the consequences of ill-health and premature death, and that’s not for me. I want to be able to play football with any future grandchildren, go travelling, socialise with friends and enjoy my retirement.

And, yes, like most people, I don’t want to look as old as I really am.

That’s why my eye was drawn to a recent study in the journal Antioxidants, which showed that the supplement luteolin slowed down the rate at which mice’s hair turned grey (as well as having overall anti-ageing properties, but more on that later). Was this the solution I sought?

Luteolin is a naturally occurring flavonoid found in celery, parsley and broccoli. There’s been lots of research on flavonoids – compounds found in fruits, vegetables, tea, and coffee. Plants use them for protection against pests, UV rays and disease.

When we consume them, they act as anti-inflammatories and antioxidants, helping fight off damage caused by free radicals (harmful molecules produced by our environment, even some bodily processes) and so potentially slow down ageing and reduce harm from disease.

Scientists at Nagoya University in Japan gave luteolin either topically (as a cream) or orally, to mice which had been genetically engineered to grey prematurely.

After 16 weeks the results were striking. While the untreated mice ended up with up to 80 per cent of their fur turning grey, the luteolin-treated group maintained their original colour.

So – does celery juice hold the key to keeping our youthful locks?

Maybe, but first let me explain why hair turns grey in the first place. As with most things in the human body, it’s down to a mix of genetics, lifestyle and bad luck.

Hair colour comes from melanocytes – tiny, pigment-producing cells in hair follicles.

These cells make melanin, the same stuff that determines your skin and eye colour.

But, as we age, our melanocytes slow down, produce less pigment, and eventually die off altogether.

For some, this happens earlier than others. And if you’re one of the unfortunate few who started finding greys in your 20s, you can probably blame your parents.

Premature greying is largely genetic, although other factors might speed things up – for example, smoking; deficiencies in zinc, copper or vitamin B12; and even stress.

We’ve all heard stories of people going grey overnight during times of extreme pressure.

While that’s a bit of an exaggeration, a 2020 study by Harvard University found chronic stress can deplete the melanocyte cells.

The researchers discovered that stress triggers the release of norepinephrine, which over-stimulates melanocyte cells and then causes a crash in their numbers, and a subsequent loss of melanin.

But whatever the cause, once the melanocytes are gone, they’re gone. No more melanin means no more colour – and suddenly your once dark, blonde or red hair starts turning grey.

However, other lifestyle factors may help slow down greying.

For instance, regular exercise, which improves circulation, ensuring that hair follicles receive a steady supply of oxygen and nutrients. It also lowers inflammation and oxidative stress – the damage caused by free radicals – which are both known to accelerate ageing.

But up until this new study scientists have been unable to find a magic bullet for preventing greying.

What the Japanese research team discovered is that luteolin helps maintain levels of endothelin, a peptide (a small protein) that’s essential for keeping melanocytes functioning properly.

This means that by preserving endothelin, luteolin might help hair maintain its colour. In fact, the luteolin story is even more interesting than just this.

The researchers also found that luteolin reduced activity of the gene p16INK4A. This gene is a key marker of cell ageing – it encourages cells to stop dividing and rejuvenating. And its activity increases as we age, telling more and more cells to give up.

In simple terms, by reducing this gene’s activity, luteolin isn’t just protecting melanocytes, it’s potentially slowing down the ageing of the very cells that keep hair pigmented in the first place.

This could help explain the results of a study from 2017, published in the European Society of Cardiology, which showed that people who had a higher percentage of grey or white hair had an increased risk of coronary artery disease.

The researchers hypothesised that the same mechanisms driving hair greying – oxidative stress and DNA damage – might be driving ageing and heart disease.

Could having premature grey hair therefore be a marker of premature ageing? And could luteolin help slow the onset of diseases of old age – heart disease, cancer and Alzheimer’s – as well as the onset of grey hair?

Luteolin is thought to work as an anti-inflammatory and antioxidant, reducing the wear and tear that builds up in our cells over time.

But thanks to its effect on the activity of the p16INK4A gene it effectively interferes with a process called cellular senescence – this is what happens when a cell gets too old, damaged or stressed and it stops dividing.

Think of it like an old car whose owner has decided to take it off the road but has left it sitting there, rusting away, no longer able to move. That’s what senescent cells do. They don’t die, but they stop functioning properly, and over time, they start clogging up tissues and releasing inflammatory signals that can speed up ageing.

But before you start ordering a luteolin supplement online, there are some things to consider.

Most of the research so far has been in animals and in labs. Mice are not humans, and what works in a lab doesn’t always translate to real-world benefits.

Then there’s the question of side-effects. While luteolin is generally safe, taking too much could interfere with hormone levels, particularly oestrogen as it can bind to oestrogen receptors. It might also interact with certain medications, such as blood thinners.

But the main issue is its theoretical risk of cancer.

The problem is that the p16INK4A gene is important in stopping the uncontrolled division of cells – otherwise known as cancer.

So while luteolin encourages cells to continue dividing and to stay youthful by reducing uncontrolled division, theoretically this could raise the risk of cancer; this is unproven by any studies but certainly scientifically possible.

So, should you be taking luteolin to slow ageing and stop your hair going grey?

The honest answer is that we don’t know yet. It’s a classic case of more research needed.

Until then, the safest advice is to eat more luteolin-rich foods – those celery sticks and broccoli stems may help delay grey hairs as well as the diseases of old age.

@drrobgalloway